This typically happens when your atomic positions are not exactly
symmetric with the symmetry you are assuming ("exactly" = "according to
the criteria used by QE"). It is not possible to say more since you did
not report your atomic positions
Paolo
On 8/15/2025 10:01 AM, Barsha Pal wrote:
Hello, I have a structure which has ibrav=6, Tetragonal P lattice, I am
using celldm 1 and 3.
My desired symmetry group is P-421m with space group 113. But when I run
my structure it shows point group :
point group C_2v (mm2)
there are 4 classes
the character table:
E C2 s_v s_v'
A_1 1.00 1.00 1.00 1.00
A_2 1.00 1.00 -1.00 -1.00
B_1 1.00 -1.00 1.00 -1.00
B_2 1.00 -1.00 -1.00 1.00
This point group is not possible in Tetragonal (ibrav =6). It belongs to
the orthorhombic lattice with space group no 35. I don't understand what
the error is. How do I decide my lattice and point group? (space group
113 was confirmed by another software for the same structure)
input file is this :
&CONTROL
calculation = "scf"
outdir = "/path/"
prefix = "name"
pseudo_dir = "/path/"
verbosity = "high"
/
&SYSTEM
celldm(1) = 12.99636895
celldm(3) = 2.211372174
degauss = 1.00000e-02
ecutrho = 1440
ecutwfc = 180
ibrav = 6
nat = 8
ntyp = 2
occupations = "smearing"
smearing = "gaussian"
/
&ELECTRONS
conv_thr = 1.00000e-08
electron_maxstep = 200
mixing_beta = 7.00000e-01
/
K_POINTS {automatic}
10 10 1 0 0 0
ATOMIC_SPECIES
A 0 A.pbe-dnl-rrkjus_psl.1.0.0.UPF
B 0 B.pbe-nl-rrkjus_psl.1.0.0.UPF
ATOMIC_POSITIONS {crystal}
Kindly guide me.
Ashley Cooper
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--
Paolo Giannozzi, Dip. Scienze Matematiche Informatiche e Fisiche,
Univ. Udine, via delle Scienze 206, 33100 Udine Italy, +39-0432-558216
_______________________________________________________________________________
The Quantum ESPRESSO Foundation stands in solidarity with all civilians
worldwide who are victims of terrorism, military aggression, and indiscriminate
warfare.
--------------------------------------------------------------------------------
Quantum ESPRESSO is supported by MaX (www.max-centre.eu)
users mailing list [email protected]
https://lists.quantum-espresso.org/mailman/listinfo/users
